The present invention relates to an electric motor comprising a temperature monitoring device.
With every electric motor that is supplied with power using a current converter, the operating temperature is typically monitored to protect the motor. The temperature is usually monitored using temperature sensors, the sensing elements of which are positioned in the direct vicinity of windings of the electric motor. The temperature sensors have specific temperature/resistance characteristics. Temperature sensors of this type usually have a resistance value that increases as the operating temperature increases, which corresponds to a positive temperature coefficient of the temperature sensor. Temperature monitoring and temperature tripping in the electric motor can be realized with the aid of temperature sensors. To monitor temperature, a temperature value detected by the sensor is unequivocally assigned to a certain resistance value. Temperature tripping can be thought of as a thermal switch that is tripped when a certain threshold value is reached and disconnects the electric motor from the current converter that supplies power until the temperature drops back below the threshold value.
Problems often occur in practical application due to the fact that regulating devices in electric motors are not compatible with temperature monitoring devices. In particular, purchasers of electric motors powered by current converters are often forced to select the regulating device that is compatible in terms of the temperature sensor and/or accept the fact that a temperature monitoring sensor system in the electric motor must be adapted in a complex manner to sensor characteristics of temperature sensor inputs of the regulating device using temperature sensors with different temperature characteristics.